Electric switch



June 26, 1934. F. T. BREWER ET AL 1,964,426

ELECTRIC swmcn Filed Nov. 28. 1932 3mm frunzz s T511 vv r fa/vznzfwgrn r Patented June 26, 1934 UNITED STATES ELECTRIC SWITCH Francis '1. Brewer and Calvin J. Werner, Dayton,

Ohio, assignors, by mesne assignments, to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application November 28, 1932, Serial No. 644,578

10 Claims.

This invention relates to a switch for controlling an electrical circuit, and more particularly to a switch for that purpose having a temperature responsive control thereon.

An object of this invention is to provide a switch that can be manually operated to two positions and automatically operated from one of said positions to the other of said positions in response to a temperature change.

Another object of this invention is to provide a manually operable switch for controlling an electrical circuit, said switch being provided with means for effecting automatic control in response to the heating effect of the current in said circuit.

Another object of this invention is to provide in combination with a switch a thermostatic con trol having resilient means for aiding the action of the thermostat and reducing the necessary movement of the thermostat for effecting the control.

Another object of this invention is to provide a switch embodying means for opening and closing the contacts with a snap action in response to movement of an operating member, and having reacting resilient members for improving the operation of a thermostatic control.

Further objects and advantages of the present invention will be apparent from the following description. reference being had to the accmpanying drawing wherein a preferred embodiment of one form of the present invention is clearly shown.

In the drawing:

Fig. 1 is a plan View of the switch with the cover removed. various elements of the switch being shown in the circuit opening position.

Fig. 2 is a view similar to Fig. 1, with the elements of the switch shown in the circuit closing position. and with one extremity of the path of motion of the operating lever in one direction indicated by dot-and-dash lines.

Fig. 3 is a sectional view taken substantially along the line 3-3 of Fig. 1.

Fig. 4 is a sectional view taken substantially along the line 44 of Fig. 2.

Fig. 5 is a sectional view taken substantially along line 5-5 of Fig. 1.

Fig. 6 is a View of the pivotal support member taken substantially in the direction of arrow 6 of Fig. 5.

'7 is an elevation of the heating element u ed with the switch.

With particular reference to the drawing, a base 10 is made of any suitable insulating material such as molded bakelite, and forms a mounting for the elements of the switch. A pivotal support member 12, having substantially horizontally extending arms 14 and 16 with pivot lugs 18 and 20 respectively at their ends, is secured to the base or mounting 10 by any suitable fastening means such as rivets 22 and 24. The horizontal arm 16 and pivot lug 20 are formed on the end of the support member 12, while the arm 14 and lug 18 are formed from material punched from an opening 26 in the support member 12. An operating member 28, having extending bifurcated arms 30 and 32, is supported by the support member 12, and bifurcations 34 and 36 in the ends of the arms 30 and 32 respectively, straddle one side of the lugs 18 and 20 respectively to form a pivotal mounting that permits movement of the operating member 28. The arms 30 and 32 are separated near their bifurcated or pivotally mounted ends, and are formed so that their opposite end portions extend adjacent the sides of a central strip 38. The portions of the arms 30 and 32 that extend adjacent to the sides of the central strip 38 extend from the ends thereof to within the confining limits defined by a housing 42 formed by the base 10 and a cover 40, which cover is indicated by dot-and-dash lines of Fig. 4. An elongated aperture 44 is provided in the housing 42 intermediate the base 10 and the cover to permit passage of the arms 30 and 32 therethru. A grip 46 preferably made of insulatingqnaterial is provided on the outer end of the extending arms 30 and 32 and is secured thereto' by any suitable fastening means such as a rivet 48. The arms 30 and 32 and the central strip 38 are preferably secured together by spot welding at a position such as 50. A rivet member 52 having shoulder portions 56 and 58 extends thru apertures 62 and 64 in the separated portions of the arms 30 and 32 respectively and thru an aperture in the central strip 38, and is secured to the arms 30 and 32 to form a. spacer or brace.

A carrying member 66, having extending bifurcated arms 68 and 70 secured to a central strip 72 by any suitable fastening means such as a rivet '74, is pivotally supported by the support member 12. and bifurcations 76 and '78 and the ends of the arms 68 and '70 respectively straddle the sides of the lugs 18 and 20 respectively opposite the sides straddled by the bifurcations 34 and 36. Edges such as 71 and 73 of the arms 68 and '70 are folded over the central strip 72 to insure maintenance of the relative positions of the central strip '72 and arms 68 and 70. A spring or resilient member 80 couples the operating member 28 to the carrying member 66 to urge the arms 30 and 32 and the arms 68 and 70 against their respective sides of the lugs'18 and 20, and permits control of the carrying member 66 thru movement of the operating member 28. The spring is connected to the operating member 28 thru an aperture 82 in the central strip 38, and to the carrying member 66 thru an aperture 84 in the central strip '72. A circuit closing element or contact member 86 is secured to the carrying member 66 opposite the pivotally mounted end thereof. The circuit closing element or contact member 86 preferably has a head portion 88 at one end and extends thru an aperture 90 in the central strip 22. A sleeve 92 preferably surrounds a portion of the circuit closing element 86 on the side of the central strip '72 opposite the head portion 88, and serves as a spacer so that the circuit closing element 86 is secured in place by riveting the end of the circuit closing element 86 adjacent one end of the sleeve 92.

A stationary contact member 94 has an extending portion 96 that acts as a resilient mounting for a contacting portion 100, formed on the member 96 by a reverse bend 98, and is secured to the base 10 by any suitable means such as a bolt 102 having a cooperating washer 104 and nut 106. The contacting portion 100 is in alignment for engagement with one end oi! the circuit closing element 86. Another contact member 108, having an extending portion 110 that forms a resilient support for a contacting portion 112 formed on its end, is mounted within a cover element 114 having drop sides 116 and 118. One end of the contact member 108 extends thru a slot 120 in the cover element 114 to provide a guide for that end, and the other end 01' the contact member 108 as well as one end of the cover element 114 are secured to the base 10 by any suitable means such as a bolt 122 having a cooperating nut 124 and washer 126. The contact member 108 is normally biased so that the contacting portion 112 is urged against the circuit closing element when in engagement therewith. The bolt 122 also has a washer 128 and a nut 130 thereon so as to form one binding post or terminal for the switch, for making connections to a lead such as 132 of the circuit to be controlled by the switch.

A support member or anchor 134 is secured to the base 10 by any suitable means such as screws 136 and 138. The support or anchor 134 has an upright or projecting portion 140 to which one end of a tnermostatic member 142 is secured or anchored by any suitable means such as rivets 144 and 146. The other end of the thermostatic member is adapted to engage a projecting curved portion 148 on the central member 38 of the operating member 28. A heating element 150, one view of which is best shown in Fig. 7 has one end secured in position by the bolt 102, and makes electrical connection therewith. That end 01' the heating element 150 is secured intermediate the washer 104 and a washer 152. The other end of the heating element 150 is held in position by means of a bolt or other suitable fastening and connecting means 154 and a cooperating washer 156. The bolt 164 also makes electrical connection with the heating element 150 and preferably has cooperating nuts 155 and 157 and a terminal lug 159 to form the other terminal or binding post of the switch for making connection to the circuit to be controlled. The heating element 150 is curved so as to be in the proximity oi, and in heat conducting relation with the 1 11612110- static member 142.

In the operation of the switch, the elements thereof assume substantially the position shown in Figs. 1 and 3 when the switch is in the circuit opening or contact disengaged position. By movement of the operating lever 28 about its pivotal mounting, and toward the right as viewed in the drawing, the center line of action of the spring or resilient member 80 is caused to cross the axis of the carrying member 66 and thus effect movement of the carrying member about its pivotal mounting by virtue of the force applied to that member by the spring or resilient member 80. The carrying member is thus caused to assume substantially the position shown in Figs. 2 and 4, and the circuit closing element or contact member 86 is engaged with the'contacting portions 100 and 112 of the contact members 94 and 108 respectively to close the circuit between those contact members.

As the operating member 28 is moved from left to. right, as viewed in the drawing, the projection or curvedportion 148 of the central member 38 engages the resilient thermostatic member and causes it to flex. Then, in order to effect movement of the carrying member 66, the operating member 28 may be moved to a position substantially as shown by the dot-and-dash lines of Fig. 2. When the operating member 28 assumes a position substantially as shown by the dot-and-dash lines of Fig. 2 the resilient thermostatic member 142 is flexed to a position substantially as indicated for that member by the dot-and-dash lines. Due to the resilience of the thermostatic member 142, the operating member 28 is forced back toward the other extremity of its path of motion and to a position substantially as shown in Fig. 2. The motion thus caused by the resilience of the thermostatic member 142 does not normally cause the center line of action of the spring or resilient member 80 to cross the axis of the carrying member 66, and hence the position of the carrying member 66 is not changed. However, the motion of the operating member 28 necessary to effect movement of the carrying member 66 is thereby reduced so that the flexure of the thermostatic member 142 due to. a temperature change need only be small to cause disengagement of the contacts due to that temperature change. In fact, the resilient thermostatic member 142 is normally biased so that at ordinary temperature the forces due to the resilience of the thermostatic member and the spring or resilient member 80 neutralize and cause the operating member 28 to come to rest at a position substantially as shown in Fig. 2. And, the necessary movement for operating the switch, may be adjusted by varying the biasing of the resilient thermostatic member. The posi-- tion assumed is the normal position of rest of the operating member when the contact or circuit closing element 86 is in the circuit closing position, and as is apparent from the drawing this normal position of rest is intermediate the extremities oi the path of motion of the operating member. When in this position, the circuit closing element 86 may be'manually operated to the circuit opening position by movement of the operating member 28.

The circuit thru the switch is formed thru the bolt 122, contact member 108, circuit closing element 86, contact member 94, bolt 102, the heating element 150 and the bolt 154. Hence, the temperature of the heating element 150 is afiected and controlled by the current flowing thru the circ it, controlled by the switch. It may therefore b said, that the switch is automatically controlled so as to open the circuit in response to an ab normal current flowing therethru.

While the form of embodiment of the present invention as herein disclosed, constitutes a pre-v ferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A thermal responsive snap switch, compris ing in combination, a stationary contact, a pivotally mounted contact carrying member having a contact mounted thereon in alignment for engagement with said stationary contact, a pivotally mounted operating member, a spring operatively coupling said operating member with said contact carrying member, means'including said operating member and said spring for actuating the contact l carrying member to engage anddisengage said contacts, a resilient thermostatic member operatively engaging the operating member when said contacts are engaged, said resilient thermostatic member being normally biased so as to be flexed when the operating member is moved to effect engagement of said contacts so that said operating member will thereby be moved back part way toward its position to effect disengagement of said contacts.

2. A thermal responsive snap switch, comprising in combination, a circuit closing element arranged to be operated to a circuit closing position and to a circuit opening position, a carrying member carrying said circuit closing element to each of said positions, said carrying member being biased to each of said positions when operated thereto, an operating member for actuating said carrying member, a resilient thermostatic member operatively engaging-said operating member when said circuit closing'element is operated to the circuit closing position, said resilient thermostatic member being flexed to permit movement of said operating member beyond the point of operative engagement therewith, said resilient thermostatic member also effecting movement of said operating member due to the'resilience of said thermostatic member, and means including said thermostatic member for operating said circuit closing element to the circuit opening position in response to an abnormal condition in the circuit. v

3. A thermal responsive snap switch, comprising in combination, a circuit closing element operable to a circuit closing position and to a circuit opening position, acarrying member carrying said circuit closing element to each of said positions, an operating member for moving the carrying members between said positions, a spring connecting the operating member and the carrying member for effecting snap action of the circuit closing element each way between said positions 'upon operation of the operating member, a resilient thermostatic member for operatively engaging the operating member when said operating member is in position to effect operation of the circuit closing element to the circuit closing position, said resilient thermostatic member being normally biased to urge said operating member toward the position at which snap action of the circuit closing element to the circuit opening position is effected, and means including said thermostatic member for actuating the circuit closing element to the circuit opening position in response to a temperature change.

4. A thermal responsive snap switch, comprising in combination, a. circuit closing element op erable to a circuit closing position and to a circuit opening position, a carrying member carrying said circuit closing element to each of said positions, an operating member for moving the carrying member between said positions, resilient means for effecting snap action of the circuit closing element each way between said positions upon operation of the operating member, a resilient thermostatic member for operatively engaging the operating member, said resilient thermostatic member being normally biased to a position to urge said operating member to a position intermediate the extremities of the path traversed by said operating member, and means including said biasing of said thermostatic member and the effect of temperature change upon said thermostatic member for effecting operation of said circuit closing element from one of said positions tothe other. 1

5. A thermal responsive snap switch, comprising in combination, a circuit closing element operable to a circuit closing position and to a circuit opening position, a carrying member carry ing said circuit closing element to each of said positions, an operating member for actuating the carrying member and having a circuit closed and a circuit open position, said circuit closed position being intermediate the extremities of the path of motion of said operating member, resilient means for effecting snap action of the circuit closing element in response to movement of the operating member, thermostatic means for effecting a change of position of said operating member in response to a temperature change, and means for automatically moving said operating member from the extremity of its path of 110 motion in one direction to its circuit closed position, whereby the necessary movement due to said thermostatic means is reduced.

6. A thermal responsive switch, comprising in combination, a circuit closing element operable 115 to a circuit closing position and to a circuit opening position, a carrying member carrying said circuit closing element to each of said positions, an operating member for actuating the carrying member and also having a circuit open and a nor- 120 mal circuit closed position, said circuit closed position being intermediate the extremities of the path of motion of said operating member, means for effecting snap action of the circuit closing element from the circuit closing position, 125 thermostatic means for effecting a change of position of said operating member in response to a temperature change, and means for automatically moving said operating member from. the extremity of its path of motion in one direction 130 to its normal circuit closed position, whereby the necessary movement due to said thermostatic means is reduced.

7. A thermal responsive switch, comprising in combination, a circuit closing element operable to a circuit closing position and to a circuit opening position, a carrying member for carrying said circuit closing element to each of said positions, an operating member for actuating the carrying member and having positions corresponding to those of the circuit closing element, one of the normal positions of the operating member being intermediate the extremities of the path of motion of said operating member, thermostatic means for effecting a change of position of said operating member in response to a temperature change, and means for inherently moving said operating member from the extremity of its path of motion in one direction to one of its normal positions, whereby the movement of said operat- 150 ing member due to said thermostatic means and necessary to change the position or the circuit closing element is reduced.

8. A thermal responsive switch, comprising in combination, cooperating contacts, a movable member supporting one of said contacts and adapted to effect engagement and disengagement of said contacts, an operating member for actuating the movable member, resilient means coupling said members to effect engagement and disengagement of said contacts with a snap action, a thermostatic element for actuating said movable member in response to a temperature change, and means effecting movement of said operating member in one direction against the urging force of said resilient means, thereby reducing the movement of said operating member necessary to change the relation of said contacts.

9. In a manually operable switch, the com- ,bination comprising, pivoted elements each operable between two positions, and a heat responsive controlling means including a resilient thermostatic member anchored at one of its ends and having its other end free to operatively engage one of said pivoted elements when that element is between said positions, the resilience of said thermostatic member permitting that member to yield and then to urge said one element toward its other position to a normal position of rest, a heating element associated with said thermostatic member, and means including said thermostatic member and its operative engagement with said pivoted element for e fl'ecting movement of said pivoted elements in response to temperature change of said heating element.

10. In a manually operable switch, the combination comprising, movable elements'each operable between two normal positions of rest, resilient means connecting said elements so that movement of one of said elements past a predetermined position effects snap movement of the other, a resilient thermostatic member anchored at one of its ends and having its other end free to operatively engage one or said movable ele ments to resist movement of that element in one direction and return it to one or its normal positions of rest, and means including said thermostatic member for moving said element to its other normal position of rest in response to a temperature change.

FRANCIS T. BREWER. CALVIN J. WERNER. 

